Improvement in metallic grinding-mills



I H. B. STEVENS. v I llotallic Grindinglills.

No. 137,503. Patented April1,1873.

i gal/2%) am Z UNITED STATES PATENT OFFICE.

HENRY B. SrEvENs, 0F BUFFALO, NEW YORK, ASSIGNOR TO GEORGE L. SQUIER, OF SAME PLACE.

IMPROVEMENT IN METALLIC GRINDING-MILLS.

Specification forming part of Letters Patent No. 137,503, dated April 1, 1873; application filed February 5, 1873.

To all whom it may concern:

Be it known that I, HENRY B. STEVENS, of the city of Buffalo, in the county of Erie and State of New York, have invented certain Improvements in Corn and Grain Mills, of which the following is a specification:

My invention relates to a class of small mills usually driven by hand or other light power, and employed in grinding corn and other grain in which the grinding-parts consist of a metallic cone revolving withina correspondingly shaped concave. The object of my invention is the construction of a machine which is adapted for grinding wet or parboiled corn, such as is used in making tortillas, as well as for grinding the grain in a dry state.

Previous to myinvention the grinding cones, and concaves of this class of mills have been constructed with spiral grooves for insuring the passage of the grain through the mill.

This spiral form of the grooves of the concave prevents the grooves being dressed or sharpened by the use of an ordinary file as they become worn off, while the grooves of the cone can be readily dressed by this means. These grooves have been arranged, as heretofore used, so that as the cone revolves the Straight edges of the grooves thereof will move toward the straight edges of the grooves of the concave and cut or break the corn between the sharp edges of the grooves as they pass each other. In mills of this construction the principal labor is performed by the edges of the grooves, which soon become worn off, and the eificiency of the machine correspondingly impaired. The object of my invention among others is to remedy these defects.

The invention consists, first, in the combination, with a grinding-cone, constructed with a square or polygonal smaller end, of a concave, provided with notches, whereby in certain positionsof the cone a number of openin gs are formed between each side of thepolyg onal end of the cone and the concave, which allow only one kernel of corn to enter at a time, thereby insuring a uniform feed; second, in the combination and arrangement, with the cone and concave, constructed as described,

and provided with a cylindrical mouth, of a feeding-screw secured to the polygonal end of the cone and revolving in the cylindrical mouth of the concave, for the purpose of conveyin g wet or parboiled corn to the grindingsurfaces; third, in the combination, with the cone, provided with a feeding-screw, and the concave, provided with a cylindrical mouth, of a spiral recess or guide-way formed in the latter for assisting in conveying the material to the grinding-surfaces; fourth, in the combination, with the grinding-cone and concave and screw-bolts for holding the latter in place, and loosely fitted in holes in the flanges of the concave, of rubber blocks or springs, arranged on said bolts between the flanges of the concave and the screw-nuts, whereby the automatic adjustment of the concave in an axial direction and concentrically with the cone is permitted.

In the accompanying drawing, Figure 1 is a side elevation of my improved mill. Fig.2 is a section in line as a, Fig. 1. Fig. 3 is a bottom plan view of the concave. Fig. 4 is a topplan "iew of the cone. Fig. 5 is an elevation of the concave and cone with the agitatingpin in place. Fig. 6 is a similar fragmentary view with the cone slightly turned. Fig. 7 is an elevation of the concave with its cylindrical mouth in section. V

Like letters designate like parts in each of the figures.

A is the supporting-frame of the mill, preferably consisting'of a block of wood capable of being secured by screw-bolts at either to any suitable vertical or horizontal object, as most convenient. I) I1 are the metallic boxes secured in the block A for receiving the spindle c, which is provided at one end with a hand-crank, d, or a pulley, when the mill is driven by other than handpower. E is the metallic cone, mounted on the opposite end of the spindle c, and F the concave surrounding the cone E, and secured to the block A by screwbolts n n, which pass snugly through the block and loosely through holes in' the flanges 0 0 of the concave, so as to allow the concave a limited play on the same. 1) are the rubber blocks or springs fitted on the bolts 11, and arranged between the socketed flanges of the concave and the socketed washers q, arranged under the thumb-screws 7". By turning the latter the concave is axially adjusted. The rubber blocks 12 allow the concave a slight lateral movement so as to insure an adjustment concentric with the cone to compensate for any irregularities in the mounting of the parts, whereby an unequal wear thereof and an imperfect grinding of the grain, which results from an unequal adjustment, is prevented. These blocks alsopermit a slight axial adj ustmerit of the concave, adapting the same to a variable feed and preventing the clogging and stoppage of the machine. The greater portion of the surface ofthe cone E is that of a true cone, except at the smaller end, which is contracted to a square, 0, as shown in Fig. 4, or a polygon of a suitable number of sides, according to the size of the cone. fare the curved or spiral grooves, arranged on the cone E, one starting from each corner of the square 6, while the rest are arranged intermediate and equidistant at the base of the cone, but converging at the smaller end thereof toward the corners of the square 6, as clearly shown in, Fig. 4. 9 represents the straight grooves of the concave F converging toward the apex thereof, as clearly shown in Fig. 3. These grooves, preferably, terminate before they reach the base of the concave and cone, so

' as to leave a narrow smooth surface, which insures the perfect grinding of the material before it can escape. The smaller end of the concave is provided with four notches, h, corresponding with the four sides of the square end 0 of the cone, so that when the latter is in a position opposite these notches, as represented in Fig. 5, four openings will be formed which will admit each one a kernel of corn be tween the cone and the concave. As the cone revolves the corners of its square end 6 project, more or less, into the notches h, as shown in Fig. 6, so as to obstruct the same and prevent the entrance of the corn until the sides of the square assume their former position with reference to the succeeding notches, whereby a uniform feed is insured. Us the cylindrical mouth or extension of the concave connecting with the corn-hopper I, which is secured thereto by a set-screw, pin, or other suitable means. I is the agitating-pin secured in an eccentric s'crew-holein. the square end of the cone, when dry corn is being ground, for preventing the same from becoming clogged in the mouth of the concave. When wet or side parallel with the threads of the feed screw m, to assist, the latter in conveying or forcing forward the wet or parboiled corn to the openings leading between the grindingsurfaces. r is a scraper, consisting of a flat spring secured to the block Aby a bolt, .9, and bent around one of the fastening'bolts n, so as to bear with its free end against the base of the cone E to scrape off or detach therefrom any ground material which may adhere thereto.

The spiral grooves of the cone in my improved machines run in a direction to carry forward the grain when the cone is revolved in an opposite direction from that of other machines of this class as heretofore constructed. In my improved mill, by revolving the cone as represented by the arrows in Figs. 2 and 4, the grain is disintegrated by being wedged and crushed between the beveled sides of the grooves of the two surfaces instead of being cut by the sharp edgesthereof. The

kernels of corn as they are fed to the grindingsurfaces, whether wet or dry, are first compressed between one of the sides of the square end of the cone and the curved sides of the notches h, which crushing action is continued as the material passes through the machine until it is discharged therefrom.

Advantages.

In using my improved machine the operative part of the grinding-surfaces, being the large beveled sides of the grooves, prevents. the rapid wearing of the same. The curvature grooves of the concave, which, being made straight, can be readily dressed when they become dull. The use of the screw m and spiral recess is feeds or forces forward the grain, however wet, soft, or adhesive in its character. The peculiar construction of the smaller end of the cone in connection with the recessed concave which insures the uniform feeding of the grain is a matter of greatest importance, especially with hand-machines, where the power which drives them is necessarily limited. The rubber blocks, which prevent the nuts from pressing directly against the unyielding surface of the flanges 0, permit the lateral adj ustment of the concave to accommodate itself to the cone, and prevent uneven ,wear of the grinding-surfaces and unequal grinding of the corn. The machine, which is shown in the drawing affixed to a vertical support, is readily adapted to be secured ,to a horizontal support by changing the fastening-bolts n n to thehole I claim as my invention 1. The combination, with the cone E provided with the square or polygonal end e, of the concave F, provided with notches h for insuring a regular and uniform feed, substan tially as hereinbefore set forth.

2. The combination and arrangement, with 4. The combination, with the grinding-cone the cone E and concave F, constructed as (10- and concave and fastening-boltsn,fittedloosely scribed. and having a cylindrical month, i, of in the flanges o 0, of rubber blocks 11 arranged the feeding-screw m secured in the end of the on the latter to facilitate the double adjustcone for grinding wet or parboiled corn, subment of the concave, substantially as hereinstantially as hereinbefore set forth. before set forth.

3. The arrangement, with the cone E pro- HENRY B. STEVENS. vided with feeding-screw m, and the concave v F provided with the cylindrical mouth 0', of the Witnesses:

spiral recess or way k formed in the latter to EDWARD WILHELM, assist in feeding wet or boiled grain, as herein- J NO. J. BONNER.

before set forth. 

